蛋白酶体抑制剂通过内质网应激影响前列腺癌DU145细胞的生长

目的:探讨蛋白酶体抑制剂(epoxomicin,EPO）可否诱导前列腺癌DU145细胞产生内质网应激以及内质网应激阻断剂是否可阻断这种作用。方法:不同浓度EPO处理DU145不同时间，MTS检测细胞生长情况，流式细胞仪检测细胞凋亡情况，Real-time PCR检测内质网应激相关分子mRNA表达情况；以及内质网应激阻断剂4-PBA阻断内质网应激后的情况。结果:EPO抑制DU145细胞生长，并呈现浓度梯度依赖；EPO处理组细胞凋亡率明显高于正常组，且EPO 20nmol组凋亡率高于10nmol组；CHOP、XBP-1s、GRP78 mRNA明显升高，72h最为明显；XBP-1及XBP-1s基因转录水平在EPO处理后都升高，而XBP-1s随着处理时间逐渐增加，XBP-1随着时间基因转录水平变化不明显；4-PBA可阻断CHOP mRNA表达，阻断EPO对DU145细胞数量的减少。结论:EPO抑制DU145细胞生长，并促进凋亡，其机制可能与激活内质网应激并激发CHOP、XBP-1s、XBP-1、GRP78分子表达等有关；4-PBA可阻断EPO对细胞生长抑制的影响。

Proteasome inhibitor affected the growth of prostate cancer cells DU145 via endoplasmic reticulum stress

Objective:To elucidate the role of EPO in DU145 cells,and the effect of EPO on ER-stress and its association with endoplasmic reticulum stress blocker.Methods:Cell proliferation was detected using MTS reagent and apoptosis was examined by flow cytometer after DU145 cells treated by EPO.Several mRNA associated to ER-stress were tested by real-time PCR and the 4-PBA were used to block the ER-stress.Results:Cell proliferation was inhibited in a time and dose-dependent manner by EPO.The percentage of cell apoptosis on treatment groups was higher than control group and the high-dose group was higher than that of low-dose group.EPO induced ER-stress in DU145 cells time- and dose-dependently induced GRP78,CHOP and XBP-1s mRNA,and CHOP protein expression.XBP-1s mRNA expression was raised more obviously than XBP-1 mRNA with time.CHOP mRNA expression and cell proliferation were blocked by the 4-PBA.Conclusion:The proteasome inhibitor EPO could inhibit cell growth and induce apoptosis on DU145 cells via ER-stress,which may be related to activate the expressions of ER-associated molecules such as CHOP,XBP-1s,XBP-1 and GRP78.4-PBA can block the effect of EPO on cell growth totally.